There are two basic faceplate panel and shadow mask contours utilized for shadow mask type CRT's. These basic contours are spherical and vertically cylindrical. In tubes having a spherical contour, the faceplates have the same curvatures along both their major and minor axes. The shadow masks in these tubes may vary somewhat from being truly spherical but still may be considered to be substantially spherical. In a tube having a vertically cylindrical contour, both the faceplate and the shadow mask have curvatures along their major axis but are straight along their minor axis.
Although the spherical contour and the cylinder with major axis curvature contour are adequate for most viewing situations, there still is a need for other faceplate contours to meet the needs of other viewing situations.